Encryption?

Reading a bunch of stuff about explicit images being deleted off cloud storage, I found myself wondering what happened to encryption. We can (using entirely free and open source software) pack files into encrypted archives, protected by passwords or certificates. Those encrypted archives are then immune to the depredations of content-killing bots.

... The downside is that they can't be shared as easily. But that's not a big issue for backups and can be worked around for small scale sharing. Moreover, commercial solutions are widespread; its the basis of managing content that is locked unless you've paid for it.

And yet, it is never mentioned.